"The Islamic Republic of Iran condemns the resorting to violence to achieve political goals," foreign ministry spokesman Hamid Reza Asefi told the official news agency IRNA.

"At this sensitive moment in Iraq, the Iraqi people should unite and be alert not to let any foreign forces separate them and impose their opinion on them in order to exploit them," he added.

Khoei had been based in London since the crushed 1991 Shiite uprising in southern Iraq.

A statement issued by the al-Khoei Foundation, which the slain cleric headed in the British capital for the past 12 years, accused "agents of the dictatorial regime now on its deathbed in Iraq" of being behind the assault.

The cleric was the son of the late Ayatollah Abolqassem al-Khoei, one of the main leaders of Iraq's Shiite community during the 1991 Gulf War, who died in 1992 under house arrest.

There had been speculation that Khoei, who had called for Shiite cooperation with the United States, had gone back to Najaf with help from US forces, and that his return signaled a US attempt to promote a "pro-American" current among Iraq's majority Shiite community as Saddam Hussein's regime collapsed.

Shiite Iran is the backer of a rival Iraqi Shiite opposition group, the Supreme Assembly for Islamic Revolution in Iraq (SAIRI) led by Ayatollah Mohammad Baqer Hakim.

SPACE.WIRE